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毕业论文 稀燃条件下低温等离子体协同选择性催化还原氮氧化物中催化剂的活性评价

  • 简介:毕业论文-稀燃条件下低温等离子体协同选择性催化还原氮氧化物中催化剂的活性评价,共73页,29344字,碳氢化合物选择性催化还原法是净化稀燃汽车尾气中NOX的有效方法之一。低温等离子体(non-thermal plasma,NTP)的协同(NTP-SCR和HC-
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文件大小:10.31MB
适用专业:环境工程
适用年级:大学
论文编号:209548

论文简介:
毕业论文-稀燃条件下低温等离子体协同选择性催化还原氮氧化物中催化剂的活性评价,共73页,29344字
碳氢化合物选择性催化还原法是净化稀燃汽车尾气中NOX的有效方法之一。低温等离子体(non-thermal plasma,NTP)的协同(NTP-SCR和HC-reform)可以促进催化剂的低温活性,为净化实际稀燃尾气提供了新的途径。
本文分别采用溶胶—凝胶法、浸渍法和离子交换法制备了Ag/γ-Al2O3、SnO2/γ-Al2O3、In2O3/γ-Al2O3、Ag/USY、Sn/USY和In/USY等催化剂,在固定床连续流动反应装置上评价了富氧条件下丙烯选择性催化还原NO的活性以及NTP-SCR和HC-reform两种协同方式对催化剂活性的影响,研究了不同的催化剂的制备方法和NTP的协同方式对催化剂的催化还原活性的关系。在此基础上,进一步考察了SO2对NTP协同 Ag/Al2O3催化活性的影响。
不同方法制备的催化剂在NTP协同作用下均表现出了良好的低温活性,不但活性比单独的SCR反应高,活性温度窗口也变宽;In2O3/Al2O3在400℃时表现出最高的催化活性(为99.9%),而Ag/Al2O3则表现出最好的平均低温活性(高于80%);SO2的存在严重抑制催化剂的活性,在SO2存在的情况下NTP-SCR的活化方式优于HC-reform的活化方式;分子筛负载型催化剂的SCR反应活性较差,但在NTP-SCR的协同下表现出很好的低温活性(高于50%);在NTP-SCR协同反应体系中,溶胶—凝胶法制备氧化铝负载的催化剂表现出最好的催化活性。
Selective catalytic reduction (SCR) of nitrogen oxides by hydrocarbons is considered to be one of the most efficient ways to remove NOX from lean burn automobile exhaust. Non-thermal plasma (NTP) assisting SCR (NTP-SCR) showed higher activity compared to thermal SCR, and the NTP-SCR or HC-reform make the reaction easier at lower temperature.
The Ag/γ-Al2O3, SnO2/γ-Al2O3, In2O3/γ-Al2O3, Ag/USY, Sn/USY and In/USY catalysts were prepared by the sol-gel, impregnation and ion exchange, respectively. Catalytic activity for NO reduction with propene (C3H6) in the presence of excess oxygen and the effect of the two assisting manners of NTP-SCR and HC-reform on the catalytic activity were investigated in a fixed-bed microreactor. The effects of preparation method as well as the assisting manners of NTP on the activities of these catalysts were also studies. The activities of these catalysts which Al2O3 is the support were also evaluated in the presence of SO2.
The results showed that, the catalysts prepared with various method mentioned had high activities at low temperature with the assisting of NTP, and they have not only higher activities but also wider temperature range than SCR. In2O3/Al2O3 had a highest activity at 400℃ (99.9%), and Ag/Al2O3 had a highest average activity at low temperature (>80%). The activities of the catalysts were seriously depressed by coexisting of SO2, however NTP-SCR showed higher assisting effect than that of HC-reform. The molecular sieve catalysts had low activities in SCR, but they had higher activities at low temperature with the assisting of NTP (>50%). Among the reactions with the assisting of NTP-SCR, the catalysts supported on Al2O3 with the same loading of active components prepared by sol-gel had the highest catalytic activities in the all catalysts.

目录
摘要 .................................................................................................................................................. I
Abstract............................................................................................................................................II
第 1 章 文献综述 ........................................................................................................................... 1
1.1 稀燃技术及稀燃尾气的处理........................................................................................... 1
1.2 选择性催化还原技术的特点及其局限性....................................................................... 1
1.2.1 贵金属催化剂 ....................................................................................................... 3
1.2.2 分子筛催化剂 ....................................................................................................... 3
1.2.3 金属氧化物类催化剂............................................................................................ 4
1.2.4 三类催化剂的比较与总结.................................................................................... 4
1.3 低温等离子体技术对SCR的协同作用 ........................................................................... 5
1.4 研究目的和研究内容 ...................................................................................................... 7
1.4.1 研究目的 ............................................................................................................... 7
1.4.2 研究内容 ............................................................................................................... 7
第 2 章 催化剂的制备及评价 ....................................................................................................... 9
2.1 催化剂的设计 .................................................................................................................. 9
2.1.1 载体 ....................................................................................................................... 9
2.1.1.1 活性氧化铝 ........................................................................................................ 9
2.1.1.2 分子筛 .............................................................................................................. 10
2.1.2 活性组分 ............................................................................................................. 10
2.1.2.1 Ag2O .................................................................................................................. 10
2.1.2.2 SnO2 ....................................................................................................................11
2.2.2.3 In2O3 ...................................................................................................................11
2.2 催化剂的制备 .................................................................................................................11
2.2.1 实验试剂 ..............................................................................................................11
2.2.2 制备方法 ............................................................................................................. 12
2.2.2.1 溶胶—凝胶法 .................................................................................................. 12
2.2.2.2 离子交换法 ...................................................................................................... 13
2.2.2.3 浸渍法 .............................................................................................................. 14
2.2.3 制备步骤 ............................................................................................................. 15
2.2.3.1 溶胶—凝胶法制备Ag/Al2O3、SnO2/ Al2O3、In2O3/ Al2O3催化剂 ............... 15
2.2.3.2 离子交换法制备Ag、Sn、In/Y型分子筛催化剂 .......................................... 15
2.2.3.3 浸渍法制备Ag、Sn /Y型分子筛催化剂......................................................... 16
2.3 实验装置和流程 ............................................................................................................ 18
2.3.1 实验装置 ............................................................................................................. 18
2.3.2 实验配气 ............................................................................................................. 19
2.4 分析项目 ........................................................................................................................ 19
2.4.1 催化剂的催化活性 ............................................................................................. 19
2.4.2 反应的中间产物 .................................................................................................. 19
2.4.3 SO2对催化剂活性的影响 .................................................................................... 19
第 3 章 氧化铝负载金属氧化物催化剂测试结果与讨论.......................................................... 20
3.1 NTP-SCR的协同方式对催化剂的活性影响 ................................................................. 20
3.1.1 NTP对Ag/Al2O3催化剂活性的影响.................................................................... 20
3.1.2 NTP对SnO2/Al2O3催化剂活性的影响 ................................................................ 21
3.1.3 NTP对In2O3/Al2O3催化剂活性的影响................................................................ 23
3.2 SO2对NTP协同氧化铝负载金属氧化物催化剂SCR反应的影响 ................................ 24
3.2.1 SO2对NTP的两种协同方式中催化剂活性的影响比较 ..................................... 25
3.2.2 SO2的影响下氧化铝负载金属氧化物催化剂活性比较 .................................... 26
3.2.3 SO2对NTP协同Ag/Al2O3催化剂的不同方式的影响比较 ................................. 29
3.3 小结 ................................................................................................................................ 30
第 4 章 分子筛负载金属氧化物催化剂测试结果与讨论.......................................................... 32
4.1 浸渍法制备催化剂活性评价......................................................................................... 32
4.2 NTP对浸渍法制备催化剂的活性影响 .......................................................................... 33
4.3 离子交换法制备催化剂活性评价................................................................................. 35
4.4 NTP-SCR对不同方法制备催化剂的活性影响比较 ..................................................... 37
4.5 小结 ................................................................................................................................ 38
第 5 章 结论与建议 ..................................................................................................................... 40
5.1 结论 ................................................................................................................................ 40
5.2 建议 ................................................................................................................................ 41
参考文献 ....................................................................................................................................... 43
附录Ⅰ:文献翻译 ....................................................................................................................... 45
附录Ⅱ:文献原文 ....................................................................................................................... 58


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  • 毕业论文-稀燃条件下低温等离子体协同选择性催化还原氮氧化物中催化剂的活性评价
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